The invention is related to velocity estimation systems and more specifically to a system and method for estimating an apparent closing velocity of a moving platform with respect to a stationary platform.
In many applications, for example in railroad systems, advanced, radio-based control systems are used to increase operational safety. For the railroad system to perform safely and efficiently there is a need to know which of a number of possible tracks a locomotive traveling at high speeds has taken. Most often, determining the locomotive position as it travels through a track turn-out and switches to a second parallel track is a significant challenge. In the above example, the locomotive is a moving platform.
Standard global positioning systems (GPS) and differentially corrected GPS are usually deployed to provide fairly accurate locomotive position. However, such systems do not usually provide sufficient information to track a fast moving train through a turn-out and onto a parallel track. In general, the position estimates are averaged over time in order to reduce noise and obtain a sufficient level of confidence in the position estimate. Because locomotives typically travel at very high speeds, using such a method to determine which one of the parallel tracks a locomotive is traveling on is substantially difficult.
Typically, additional sensors such as accelerometers and gyros are used to augment the global positioning systems so as to provide a more robust inertial navigation solution system. One problem with adding additional sensors to the existing GPS is the significant increase in the overall cost, complexity and failure modes of the system.
It would therefore be desirable to implement a low-cost, high-performance system that can accurately determine the position of a moving platform, like a locomotive, traveling at high speeds.